The present invention relates to an improved device for subsurface distribution of graywater for irrigation.
Research and field testing has shown that drip irrigation systems save water when compared to all other irrigation systems. It has also been shown that drip irrigation under the soil's surface further prevents evaporation loss. Irrigation systems for subsurface distribution of water have heretofore been limited to use with clear water.
Graywater comes from inside houses and includes all used water except toilet water. Graywater from showers, tubs, and clotheswashers has recently been shown to be a viable source of irrigation water. Because of the possibility of disease transmittal through contact with graywater, it must by law be distributed subsurface.
The most practical method for transporting graywater is through a pressurized tube system commonly used in clear water irrigation. However, even when filtered by most known methods, graywater contains suspended solids which eventually clog up devices designed for pressurized clear water drip systems. These systems can be on the surface or buried.
When drip irrigation systems are buried, it is an expensive and time consuming process to dig them up when they become inoperative. It is therefore very important that once buried, they stay in working order. Dogs, deer, children, gardeners, etc., can cause these systems to leak if they are not kept buried properly. The possibility of contamination would then become present.
Existing subsurface drip irrigation systems have many designs, but all revolve around the same two methods.
The first method is a pressurizable tubing usually made of a 1/2" to 3/4" pliable plastic material like polyethylene. This tubing will either have some sort of openings along its length, or have drip emitters stuck through it along its length. These openings can have different shapes and sizes, with or without internal or external structures surrounding them. These openings, as do drip emitters, control the release of pressurized water from inside the tubing to the soil, and may or may not be protected by another layer of tubing or some other method of restricting roots or soil from entering the openings.
Drip emitters have many unique abilities when used with clear water. To be effective, they must be either applied on the tubing in several places at the installation site or in the factory. Each application takes time, and each emitter costs money. Many are relatively expensive.
The second and less preferred method is a leach field. This consists of a non-pressurizable pipe usually about 3" in diameter, with holes along its entire length big enough to not clog up from graywater. The pipe is laid in a shallow trench with its holes facing down. Water entering this pipe will run via gravity to fill up the pipe, then will eventually seep down through the holes, into gravel surrounding the pipe, then slowly into the soil. Gravel is put there to keep soil from entering the pipe.
The problem with the leach field method is it requires a long linear trench be dug for the perforated pipe. Buried objects like roots and irrigation pipes, and surface objects like sidewalks, often prohibit linear digging. Existing gardens, the most common place for installation of a graywater system's distribution device, are full of these obstructions.
Accordingly, it would be desirable to provide a device which can be used for subsurface distribution of graywater under pressure, which is inexpensive to manufacture and install, which will remain safe, which will not clog up, and which can be used in obstructionist environments.